This is Quest #6 for Thunderstone Quest, first made available through the Thunderstone Quest: Back to the Dungeon Kickstarter campaign.
What Lies Beneath, the sixth quest for Thunderstone Quest, which presents a story-driven scenario for the attack on the village, can be played in normal competitive mode as well as in Barricade mode. This expansion includes more than 240 cards, six dungeon tiles, and a rulebook.
